As a senior bicycle rider who frequently travels on Crandon Boulevard, painting the bicycle lane green, and adding the rumble strips to separate it from the roadway is a no-brainer.
I don't like riding on the sidewalk because: (1) I have to dodge pedestrians, making it dangerous for both of us; and (2), it is far safer than the sidewalk at the intersecting streets and driveways because cars often block the sidewalk area as they pull out to check for oncoming traffic.
In addition, drivers reflexively check the roadway for traffic, not the sidewalk.
From personal observation, I would suggest that the bicycle lane within the village is used far more on a weekly basis by the children and adults of Key Biscayne than the occasional use, usually on weekends, by off-Islanders.
In both cases, green bicycle lanes are a stark reminder to both bikers and drivers -- stay in their own lanes.